//
//  TextSource.swift
//  划词侠 plugin
//
//  Two source modes:
//    .clipboard   — NSPasteboard.general.string(forType:.string).
//                   No permissions needed.
//    .selection   — Try NSWorkspace + AXUIElement to read the focused
//                   element's selected-text. Requires Accessibility
//                   permission. If denied, return .permissionDenied so
//                   the UI can prompt + fall back to clipboard.
//

import AppKit
import ApplicationServices

enum TextSourceMode: String, CaseIterable, Identifiable {
    case clipboard
    case selection
    var id: String { rawValue }

    var label: String {
        switch self {
        case .clipboard: return "粘贴板"
        case .selection: return "选中文本"
        }
    }
}

enum TextSourceResult {
    case ok(String)
    case empty
    case permissionDenied
    case error(String)
}

enum TextSource {

    /// Read the system pasteboard (.string type). No permissions.
    static func readClipboard() -> TextSourceResult {
        let pb = NSPasteboard.general
        guard let s = pb.string(forType: .string) else {
            return .empty
        }
        let trimmed = s.trimmingCharacters(in: .whitespacesAndNewlines)
        if trimmed.isEmpty { return .empty }
        return .ok(s)
    }

    /// Best-effort read of the *focused* UI element's selected text via
    /// AX. Requires Accessibility permission for Mio Island's host
    /// process. Returns .permissionDenied if not granted (caller should
    /// surface the banner), or .empty if granted-but-nothing-selected.
    static func readSelectionViaAX() -> TextSourceResult {
        // AXIsProcessTrustedWithOptions with the prompt option will pop
        // the system "open System Settings" sheet on first call. We
        // pass false so we don't trigger the prompt unexpectedly — the
        // UI banner explicitly tells the user where to enable it.
        let opts: NSDictionary = [kAXTrustedCheckOptionPrompt.takeUnretainedValue() as String: false]
        guard AXIsProcessTrustedWithOptions(opts) else {
            ClipperDebugLog.write("selection: AX not trusted")
            return .permissionDenied
        }

        let systemWide = AXUIElementCreateSystemWide()
        var focused: CFTypeRef?
        let focusErr = AXUIElementCopyAttributeValue(
            systemWide,
            kAXFocusedUIElementAttribute as CFString,
            &focused
        )
        guard focusErr == .success, let element = focused else {
            ClipperDebugLog.write("selection: no focused element (err=\(focusErr.rawValue))")
            return .empty
        }
        // swiftlint:disable:next force_cast
        let axElement = element as! AXUIElement

        var selValue: CFTypeRef?
        let selErr = AXUIElementCopyAttributeValue(
            axElement,
            kAXSelectedTextAttribute as CFString,
            &selValue
        )
        guard selErr == .success, let s = selValue as? String else {
            ClipperDebugLog.write("selection: no selected text (err=\(selErr.rawValue))")
            return .empty
        }
        let trimmed = s.trimmingCharacters(in: .whitespacesAndNewlines)
        if trimmed.isEmpty { return .empty }
        return .ok(s)
    }

    /// Convenience: read whichever source is active, with fallback.
    static func read(mode: TextSourceMode) -> TextSourceResult {
        switch mode {
        case .clipboard:
            return readClipboard()
        case .selection:
            let r = readSelectionViaAX()
            // If AX gave us empty (granted but nothing selected) we keep
            // the empty result — caller decides whether to fall back.
            return r
        }
    }
}